from The American Heritage® Dictionary of the English Language, 4th Edition
- n. See exine.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. the outer layer of a pollen grain or spore; the exine
from The Century Dictionary and Cyclopedia
- n. Same as exospore.
New Latin : exo- + Greek sporā, spore; see sper- in Indo-European roots.(American Heritage® Dictionary of the English Language, Fourth Edition)
It has been suggested, and apparently on good grounds, that the spore membrane consists of two layers, the exosporium and the endosporium.